An internal combustion engine includes a sleeve valve which fits between the piston and the cylinder wall in the cylinder where it rotates and/or slides. The sleeve valve moves independently from the piston so that openings in the valve align with the inlet and exhaust ports in the cylinder at proper stages in the combustion cycle. One example of such a sleeve valve is shown in U.S. Pat. No. 7,559,298, titled “Internal Combustion Engine,” which is assigned to Cleeves Engines Inc., and is incorporated in its entirety herein.
FIG. 9 illustrates a cross-sectional view of a portion of a conventional annular sleeve valve assembly 20. The sleeve valve assembly 20 includes a sleeve valve 22, an oil path-defining piece 24 and a valve seat 36. The sleeve valve 22 has a distal end 18 with an end surface 14, an inner surface 21, and an exterior surface 23. The oil path-defining piece 16 includes an oil inlet 28, a cooling passage 30, and an oil outlet 32. FIG. 9 shows the sleeve valve 22 in a closed position as the end surface 14 is in contact with the valve seat 36.
The sleeve valve 22 reciprocates between an open position and a closed position over the valve seal 26. On one side of the seal 26 is the manifold gas, either intake on one side or exhaust on the other (via port 34), and the other side of the seal 26 is cooling/lubricating oil path 27 in the oil path-defining piece 16. The combustion gases in the cylinder (not shown) heat the inner surface 21 of the sleeve valve 22 and, indirectly, the oil seal on the exterior surface 23 of the sleeve valve 22. In this embodiment, the coolant travelling through the cooling passage 30 is at least a distance t1 from the exterior surface 23 of the sleeve valve 22. A typical distance t1 is several millimeters away from the exterior surface 23 of the sleeve valve 22.
A conventional sleeve valve is often manufactured from steel. In the instance whereby the sleeve valve 22 is steel, it is very difficult to effectively cool the end surface 14 of the sleeve valve 22 during operation of the engine.
A more efficient cooling system is needed for a sleeve valve design.